Monday, November 18, 2013

A recent study in JAMA Otolaryngology--Head& Neck Surgery, in October 2013, suggested that chronic rhinosinusitis (CRS) may
be caused by an overactive immune response to normal microbes, and not
necessarily to bacterial infection. Investigators from Saint Louis University
School of Medicine in Missouri lead by Dr. Rajeev
Aurora found that patients and healthy controls tended to have qualitatively
similar microorganisms in their sinus cavity. While control patients sinus lavage
samples triggered interleukin (IL)-5 production in peripheral blood leukocytes
from patients, this did not occur with leukocytes from controls.

The investigators obtained sinus cavity
samples from thirty patients with CRS and 12 controls. They used deep sequencing to
characterize the patients' microbiomes and search for pathogens
that may potentially trigger an immune response. They also identified the immune
cells and cytokines in the specimens. Almost all the recovered fungal and bacterial species were non pathogenic . Although there were higher numbers
of these organisms in patients than in controls, the microbiomes in the two
groups were qualitatively similar. The fact that only leukocytes from patients
with CRS reacted to nasal samples from controls, suggests
that CRS patients have an abnormal immune response to normal
microorganisms.

The researchers postulated in an
interview with Reuters Health that these results indicate that immune cells
from a patient with CRS are getting activated by the microbes
found in the normal sinus. These non-virulent organisms are most likely picked
up from the air the patients breath, and therefore antibiotics cannot eliminate
them in the sinus as they re-colonize the sinus with each breath. The authors
also believe that these organisms may leads to a persistent
inflammation in people whose immune system is aberrantly sensitive to these
common organisms.

In an interview with Reuters Health Dr. Itzhak Brook, a pediatrician at Georgetown
University in Washington, D.C., who specializes in sinus infections, called the
study "innovative and provocative." However, he noted that 16 of 30
patients in the CRS group were asthma suffers and prone to
allergies. "They therefore do not represent the average patient with CRS, but a subgroup in whom the immune system is
hyperactive," Dr. Brook added that the findings shouldn't change how
doctors treat patients.

The fact that the sinus cavity in normal
individuals harbors the same bacteria (albeit in greater numbers) as infected
sinuses is not new and was describe in study done by Dr. Brook in 1981.

About Me

Dr. Itzhak Brook is a physician who specializes in pediatrics and infectious diseases.
He is a Professor of Pediatrics at Georgetown University Washington D.C. and his areas of expertise are anaerobic and head and neck infections including sinusitis. He has done extensive research on respiratory tract infections and infections following exposure to ionizing radiation. Dr. Brook served in the US Navy for 27 years. He is the author of six medical textbooks, 155 medical book chapters and many scientific publications. He is an editor of four and associate editor of four medical journals. He is a board member of the Head and Neck Cancer Alliance. Dr. Brook is the recipient of the 2012 J. Conley Medical Ethics Lectureship Award by the American Academy of Otolaryngology-Head and Neck Surgery.
Dr. Brook was diagnosed with throat cancer in 2006.

Disclaimer

This blog is not a substitute for medical care by medical professionals. Patients should consult with their personal physicians before making any decisions about their medical and surgical care. Physicians and other providers reading this blog should make independent, informed decisions about the care of their patients based on the individual facts and circumstances of each case.